alpha patterns

cmd/mxl-pattern/main.go

@@ -48,6 +48,7 @@ type appArgs struct {
 	videoFPS     string
 	videoUUID    string
 	noVideo      bool
+	videoAlpha   bool
 	videoBackend string
 
 	audioChannels     uint8
@@ -173,6 +174,12 @@ func validateMediaSelection(args appArgs) error {
 	if args.noVideo && args.audioFlowDefFile == "" && args.audioChannels == 0 {
 		return fmt.Errorf("--no-video requires audio enabled with --channel or --audio")
 	}
+	if args.videoAlpha && args.noVideo {
+		return fmt.Errorf("--alpha cannot be used with --no-video")
+	}
+	if args.videoAlpha && args.videoFlowDefFile != "" {
+		return fmt.Errorf("--alpha cannot be used with --video; set media_type to %q in the flow definition", flowdef.MediaTypeV210A)
+	}
 	return nil
 }
 
@@ -287,6 +294,7 @@ func addFlags(fs *pflag.FlagSet, args *appArgs) {
 	fs.StringVar(&args.videoFPS, "fps", "25", "Video pattern FPS")
 	fs.StringVar(&args.videoUUID, "video-id", "", "Video UUID. Will be created, if not provided")
 	fs.BoolVar(&args.noVideo, "no-video", false, "Disable video generation; audio must be enabled")
+	fs.BoolVar(&args.videoAlpha, "alpha", false, "Generate video/v210a with a moving transparent square")
 	fs.StringVar(&args.videoBackend, "backend", string(video.BackendAuto), "Video generator backend: auto, gpu or cpu")
 	// Audio pattern flags
 	fs.Uint8VarP(&args.audioChannels, "channel", "c", 0, "Amount of audio channels. Each channel: num * 1kHz")
@@ -370,7 +378,11 @@ func buildVideoConfig(args appArgs) (*video.Config, error) {
 		}
 
 		var err error
-		definition, err = flowdef.NewV210Video(
+		newVideo := flowdef.NewV210Video
+		if args.videoAlpha {
+			newVideo = flowdef.NewV210AVideo
+		}
+		definition, err = newVideo(
 			args.videoUUID,
 			args.videoWidth,
 			args.videoHeight,